Predictive value of foot pressure assessment as part of a population based diabetes disease management program

OBJECTIVE - To evaluate the effectiveness of dynamic plantar pressure assessment to determine patients at high risk for neuropathic ulceration. In choosing the cut point, we looked for an optimum combination of sensitivity and specificity of plantar pressure to screen for neuropathic ulceration. RESEARCH DESIGN AND METHODS - A total of 1,666 consecutive individuals with diabetes (50.3% male) presenting to a large urban managed care-based outpatient clinic were enrolled in this longitudinal 2-year outcome study. Patients received a standardized medical and musculoskeletal assessment at the time of enrollment, including evaluation in an onsite gait laboratory. RESULTS - Of the entire population, 263 patients (15.8%) either presented with or developed an ulcer during the 24-month follow-up period. As expected, baseline peak plantar pressure was significantly higher in the ulcerated group than in the group who did not ulcerate (95.5 ± 26.4 vs. 85.1 ± 27.3 N/cm², P < 0.001). There was also a trend toward increased pressure with increasing numbers of foot deformities, as well as with increasing foot risk classification (P = 0.0001). Peak pressure was not a suitable diagnostic tool by itself to identify high-risk patients. After eliminating patients without loss of protective sensation, using receiver operating characteristic (ROC) analysis, the optimal cut point, as determined by a balance of sensitivity and specificity, was 87.5 N/cm², yielding a sensitivity of 63.5% and a specificity of 46.3%. CONCLUSIONS - The data from this evaluation continue to support the notion that elevated foot pressure is an important risk factor for foot complications. However, the ROC analysis suggests that foot pressure is a poor tool by itself to predict foot ulcers.